The present invention relates to a semiconductor device and can be used appropriately for a semiconductor device including, e.g., an IE (Injection Enhancement) type trench gate IGBT (Insulated Gate Bipolar Transistor).
As an IGBT having a low collector-emitter saturation voltage VCE (sat), a trench gate IGBT is used widely. An IE type trench gate IGBT has been developed in which, in a cell formation area, active cell regions coupled to an emitter electrode and inactive cell regions each including a floating region are alternately arranged to allow an IE effect to be used. The IE effect reduces the likelihood of discharge of holes from the emitter electrode when the IGBT is in an ON state to thus increase the density of charges stored in a drift region.
International Patent Publication No. WO2011/111500 (Patent Document 1) discloses a technique in which, in an insulated-gate semiconductor device, between adjacent first trenches, one or more second trenches provided in parallel with the first trenches are formed and, in each of the second trenches, a first conductor is embedded via an insulating film.